1. Field of the Invention
The present invention relates to a plasma display panel (PDP), and more particularly, to a PDP having improved driving efficiency and brightness.
2. Discussion of the Background
Generally, a PDP displays images by using a discharge effect. It is thin and may have a large screen, as well as high display capacity, high brightness, high contrast, clear latent imagery, and large viewing angle. Therefore, PDPs are considered to be a next generation display device for replacing the cathode ray tube (CRT).
The PDP may be categorized as a direct current (DC) type PDP and an alternating current (AC) type PDP according to its driving voltage waveforms and discharge cell structure. In the DC PDP, charged electrons move directly between corresponding electrodes since the electrodes are exposed in the discharge space. However, in the AC PDP, a dielectric layer covers at least one electrode, and discharge occurs due to an electric field of a wall charge instead of a direct movement of charges between electrodes.
Most PDPs being produced at this time are AC PDPs, and FIG. 1 shows a typical structure for a surface discharge AC PDP. FIG. 2 shows a discharge cell of the PDP of FIG. 1.
Referring to FIG. 1 and FIG. 2, a PDP comprises a first panel 110 and a second panel 120 facing the first panel 110.
The first panel 110 comprises a plurality of stripe shaped sustain electrodes X1, . . . , Xn and scan electrodes Y1, . . . , Yn on a first substrate 111. A first dielectric layer 114 covers the sustain electrodes X1 . . . Xn and scan electrodes Y1 . . . Yn, and a protective layer 115 covers the first dielectric layer 114. As shown in FIG. 2, the sustain and scan electrodes may comprise transparent electrodes Xna and Yna, which may be formed of a transparent conductive material such as an indium tin oxide (ITO), and bus electrodes Xnb and Ynb, which may be formed of highly conductive material, respectively.
The second panel 120 comprises stripe shaped address electrodes AR1, . . . , ABm formed on a second substrate 121 and substantially orthogonal to the sustain electrodes X1, . . . , Xn and the scan electrodes Y1, . . . , Yn. A second dielectric layer 123 covers the address electrodes AR1 . . . ABM, and barrier ribs 124, which define a plurality of discharge cells, are formed on the second dielectric layer 123. Fluorescent layers 125 are formed on the second dielectric layer 123 and the sides of the barrier ribs 124. The fluorescent layers 125 comprise red, green, and blue fluorescent layers.
A discharge gas is filled in a discharge space formed by joining the first and second panels 110 and 120 together.
FIG. 3 is a timing diagram showing typical driving signals for the PDP of FIG. 1. In FIG. 3, reference numerals SAR1, . . . , SABm represent driving signals applied to the address electrodes AR1, . . . , ABm, reference numerals SX1, . . . , SXn represent driving signals applied to the sustain electrodes X1, . . . , Xn, and reference numerals SY1, . . . SYn represent driving signals applied to the scan electrodes Y1, . . . , Yn.
A basic method for driving a PDP may include sequentially performing reset, address, and sustain periods. The reset period (not shown) provides uniform charge states for all discharge cells.
In the address period A, wall charges are generated in selected discharge cells. Referring to FIG. 3, display data signals are applied to the address electrodes AR1, . . . , ABm while sequentially applying scan pulses of a ground voltage VG to the scan electrodes Y1, . . . , Yn, which are biased to Vscan. When applying the display data signals to the address electrodes AR1, . . . , ABm, a positive address voltage VA selects the discharge cells, and the ground voltage VG is applied when a discharge cell is not to be selected. Accordingly, applying the display data signal of the voltage VA forms wall charges in the corresponding discharge cells, and wall charges are not formed in the corresponding discharge cells when applying the ground voltage VG.
In the sustain period S, sustain discharge occurs in selected discharge cells by alternately applying a voltage VS to the sustain electrodes X1, . . . , Xn and the scan electrodes Y1, . . . , Yn. The discharge occurs when applying a voltage to the cells that exceeds their discharge firing voltage. The voltage applied to the cell includes the voltage VS and its wall voltage.
Referring to FIG. 2, a sustain discharge generates plasma, and ultra violet rays emitted by the plasma excite the fluorescent layers 125 to emit visible light.
Sustain discharges generate meta-stable particles of atoms and molecules. These meta-stable particles ionize neutron particles by colliding with them since the meta-stable particles have a relatively long lifetime, which may decrease the discharge-sustain and discharge firing voltages.
As shown in FIG. 2, the surface discharge type PDP may have a semicircular sustain discharge path. The meta-stable particles generated in these discharge paths may collide with the barrier ribs 124, shown in FIG. 1, and the fluorescent layers 125. Therefore, the meta-stable particles near the barrier ribs 124 and the fluorescent layers 125 may have a relatively short lifetime, which may increase the discharge-sustain and discharge firing voltages.
To solve this problem, Korean Patent Application No. 2002-0072590 discloses a method that generates a linear discharge route formed by disposing the sustain electrode and the scan electrode to face each other.
However, this method may require a high address voltage to induce address discharge, thereby reducing driving efficiency.